Datasheet AD8311 (Analog Devices)

50 dB GSM PA Controller AD8311 FEATURES
Its high sensitivity allows control at low signal levels, thus reducing the amount of power that needs to be coupled to the
Complete RF detector/controller function
detector. For convenience, the signal is internally ac-coupled.
>50 dB range at 0.9 GHz (−48 dBm to +3 dBm re 50 Ω)
This high-pass coupling, with a corner at approximately
Accurate scaling from 0.1 GHz to 2.5 GHz
0.016 GHz, determines the lowest operating frequency. Thus,
Temperature-stable linear-in-dB response
the source can be dc-grounded.
Log slope of 23 mV/dB, intercept at −60 dBm at 0.9 GHz True integration function in control loop
The AD8311 provides a voltage output, VAPC, which has the
Low power: 20 mW at 2.7 V
voltage range and current drive to directly connect to the gain

control pin of most handset power amplifiers. VAPC can swing
APPLICATIONS
from 300 mV above ground to within 200 mV below the supply voltage. Load currents of up to 6 mA can be supported.
Single, dual, and triple band mobile handset (GSM, DCS, EDGE)
The setpoint control input is applied to pin VSET and has an
Transmitter power control
operating range of 0.25 V to 1.4 V. The associated circuit

determines the slope and intercept of the linear-in-dB
GENERAL DESCRIPTION
measurement system; these are nominally 23.6 mV/dB and −59.7 dBm at 0.9 GHz. Further simplifying the application of The AD8311 is a complete low cost subsystem for the precise the AD8311, the input resistance of the setpoint interface is over control of RF power amplifiers operating in the frequency range 35 MΩ, and the bias current is typically 0.26 μA. 0.1 GHz to 2.5 GHz and over a typical dynamic range of 50 dB. It is intended for use in cellular handsets and other battery- The AD8311 is available in a 6-ball wafer-level chip scale operated wireless devices. The log amp technique provides a package (WLCSP), 1.0 mm × 1.5 mm, and consumes 7.6 mA much wider measurement range and better accuracy than from a 2.7 V to 5.5 V supply. controllers using diode detectors. In particular, its temperature stability is excellent over a specified range of −40°C to +85°C.
FUNCTIONAL BLOCK DIAGRAM LOW NOISE LOW NOISE VPOS BAND GAP GAIN BIAS REFERENCE VAPC
⋅
1.35 DET DET DET DET DET HI-Z LOW NOISE RAIL-TO-RAIL BUFFER RFIN FLTR 10dB 10dB 10dB 10dB VSET V I OFFSET INTERCEPT 23mV/dB COMPENSATION POSITIONING 250mV TO
1
1.4V = 50dB
00 5-
COMM
54 05 Figure 1.
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Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION BASIC THEORY CONTROLLER-MODE LOG AMPS CONTROL LOOP DYNAMICS BASIC CONNECTIONS RANGE ON VSET AND RFIN TRANSIENT RESPONSE MOBILE HANDSET POWER CONTROL EXAMPLE POWER-ON AND POWER-OFF INPUT COUPLING OPTIONS TEMPERATURE DRIFT DEVICE CALIBRATION AND ERROR CALCULATION SELECTING CALIBRATION POINTS TO IMPROVE ACCURACY OVER A REDUCED RANGE DEVICE HANDLING EVALUATION BOARD OUTLINE DIMENSIONS ORDERING GUIDE